Thursday, November 08, 2007

"Semantic Associations Between Signs And Numerical Categories In The Prefrontal Cortex" or MONKEYS CAN COUNT!

Read the full paper describing how Ilka Diester and Andreas Nieder performed experiments suggesting that monkeys can count integers.

Next, we should teach them number theory so they can work on prime numbers. For some adventurous monkeys, we might try calculus, set theory, or differential geometry! Oh wait, we already have such monkeys, they are called math and physics grad students! :-D

Here is the Author Summary:

We use symbols, such as numbers, as mental tools for abstract and precise representations. Humans share with animals a language-independent system for representing numerical quantity, but number symbols are learned during childhood. A first step in the acquisition of number symbols constitutes an association of signs with specific numerical values of sets. To investigate the single-neuron mechanisms of semantic association, we simulated such a mapping process in rhesus monkeys by training them to associate the visual shapes of Arabic numerals with the numerosity of multiple-dot displays. We found that many individual neurons in the prefrontal cortex, but only a few in the posterior parietal cortex, responded in a tuned fashion to the same numerical values of dot sets and associated shapes. We called these neurons association neurons since they establish an associational link between shapes and numerical categories. The distribution of these association neurons across prefrontal and parietal areas resembles activation patterns in children and suggests a precursor of our symbol system in monkeys.

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